This chapter explores the ‘welfarist’ approach to international law as developed by Eric Posner. Grounded in an economic and empirical perspective, this approach addresses the efficiency of the international legal system. As a system grounded on state will, it establishes that international law is not binding and possesses a functional scope that is limited to state cooperation. Drawing on this assumption, the chapter contends that international welfare treaties have the advantage of prevailing over human rights treaties, thus allowing the effective development of low-welfare countries with the support of higher-welfare countries.